New Analysis Suggests Earlier Start for Upright Walking

As early as six million years ago, apparently close to the beginning of the human lineage, an ancestral species had already developed the transforming ability for upright walking, scientists reported on Thursday.

A new, more detailed analysis of a fossil thigh bone found eight years ago in Kenya yielded strong evidence that the species Orrorin tugensis stood and walked on its hind limbs. The scientists said this was the earliest known example of bipedal locomotion.